About the carboy- "clean" is clean. I mean, if it's clean, there isn't any reason to scrub. I use some plastic carboys (better bottles) and buckets, so I never scrub anything with a brush unless it's a glass carboy that needs it. If it's clean to your eye, and it's free from debis, it's clean. After it's clean, then it can be sanitized.
I never use marbles or anything for dryhopping. The hops will soak up some beer, and sort of float on top. As long as the hops are in contact with the beer, you're fine.
Broken Leg Brewery
Giving beer a leg to stand on since 2006